Process for sterilizing articles and process for wrapping articles

ABSTRACT

The invention provides a method of sterilizing products and a method of packaging them, which little denature of the products, little concern with rusting or corrosion of the equipment, permit a safe working environment, and can shorten the treatment time, and this invention relates to a method of sterilizing products by adding hydrochloric acid to water not containing sodium chloride, passing the resulting fluid to a diaphragm-less electrolytic bath, electrolyzing the fluid, collecting the electrolytic water, diluting the collected electrolytic water with water, and sterilizing products with both the diluted electrolytic water and ultraviolet radiation; and to a method of packaging products with packaging members sterilized by the above process.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method of sterilizing products and amethod of packaging products.

In more detail, the present invention relates to a method of sterilizingproducts using in combination ultraviolet rays and electrolytic waterobtained from water not containing sodium chloride, and to a method ofhygienically packaging products using in combination the aforesaidelectrolytic water and ultraviolet rays.

In the present invention, the term “product” means food and drugs.

Also, in the present invention, “practically neutral” means having a pHclose to neutral, and means in particular being in a pH range of 5.0 to6.5.

2. Description of the Related Art

Previously, as methods of sterilizing products, various methods such asheating sterilization, chemical sterilization, or irradiationsterilization have been practiced; known methods of irradiationsterilization include irradiation with γ rays, x rays, or ultravioletrays. Also, methods using chemicals include for example methods usinghalogen-based sterilizing agents such as chlorine or iodine, methodsusing oxygen-based sterilizing agents such as hydrogen peroxide orozone, and methods using gaseous sterilizing agents such as ethyleneoxide or propylene oxide. Of these methods, hydrogen peroxide isemployed in a wide range of applications on account of the vigorousoxidizing action of the oxygen which it generates (see “New Food ProductSterilization Engineering” by Isao Shibazaki, August 1983, Korin CompanyLimited).

As described above, in particular in the field of food products, variousmethods of sterilization are employed. In particular in packagingproducts using a packaging member, sterilization of the packaging memberis performed in order to guarantee hygiene. That is, in for exampleretort food products, except for the case where sterilization isconducted after packaging the food product, when packaging the foodproduct, it is important to package this in a hygienic condition bythoroughly sterilizing the packaging member.

For sterilizing a packaging member, the various sterilization methodsdescribed above may be used alone or in combination. For example, takingthe case of a filling machine for filling paper containers with creamsoup, the packaging member is a paper container, this paper container issterilized by bringing it into contact with 0.1% hydrogen peroxide thenirradiating it with ultraviolet rays, after which it is filled withseparately sterilized cream soup, sealed and packaged (see for exampleWO 80/01457, Catalogue of Tetrapack Inc.).

However, in recent years, the sterilizing effect of electrolytic waterobtained by electrolysis of various solutions has become known, andmethods of sterilization using such electrolytic water have beenestablished. For example, sterilization by a combination of ultravioletrays and electrolytic acidic water, by replacing the 0.1% hydrogenperoxide referred to above by electrolyzed water, may be considered(Laid-Open Japanese Patent Publication No. 9-154924. Hereinbelow thiswill be referred to as the prior art).

In this prior art, “electrolytic water” is taken to mean ordinaryconventional electrolytic water; such conventional ordinary electrolyticwater was obtained by electrolysis of water to which sodium chloride hadbeen added (Japanese Patent No. 2627100).

In this prior art referred to above, since electrolytic water obtainedby electrolysis of water to which sodium chloride had been added wasemployed, there was a residual content of sodium chloride tending tocause contamination of the equipment by sodium chloride.

This therefore gave rise to the problem that crystals of sodium chloridemight be deposited on the surface of the sterilized product or, if usedfor product packages, sodium chloride might be left behind on thepackaging member affecting the taste of the packaged food product.

A further problem was that sodium chloride gave rise to variousdifficulties as far as the equipment was concerned, such as corrosionbeing caused by adhesion of sodium chloride to metal surfaces of theequipment, making this method unsuitable for use over a long period.

Furthermore, in the prior art referred to above, the electrolytic waterwas usually used in a strongly acidic condition. However, the dissolvedcondition of chlorine in strongly acidic electrolytic water is unstableso the dissolved chlorine is volatilized in a short time as chlorinegas, giving rise to the problem of instability of the sterilizationeffect. In order to ensure a satisfactory sterilization effect, it wastherefore necessary to set the chlorine concentration of theelectrolytic water beforehand at a high level. This was thereforeundesirable in view of the problem of corrosion of metallic surfaces bythe chlorine or in regard to safety of the working personnel etc.

Furthermore, in the prior art referred to above, when ultravioletirradiation was performed, it was necessary to perform irradiation withultraviolet rays for a long time of 10 seconds or more, preferably morethan 30 seconds. This led to the problem, in for example, a machine forpacking cream soup, that the treatment time when performingsterilization of the paper container was long, lowering the overallproductive capacity. That is, this prior art was unsuited to massproduction and its industrial utilization as a method for packagingproducts was attended by many difficulties.

Specifically, the prior art referred to the above using conventionalelectrolytic water suffered from the problems of being unsatisfactory inregard to product quality, equipment life, maintenance and management,ensuring the safety of working personnel, and of being unsuited to massproduction.

SUMMARY OF THE INVENTION

The present invention provides a method of sterilizing products and amethod of packaging products, that little denature the products, littleconcern with rust or corrosion and the like of the equipment, thataffords a safe working environment, and can shorten the treatment time.

The present invention relates to a method of sterilizing products, whichcomprises adding hydrochloric acid to water not containing sodiumchloride, passing the resulting fluid through a diaphragm-lesselectrolytic bath, subjecting the resulting fluid to electrolysis,collecting the electrolytic water, diluting the electrolytic water withwater, and then sterilizing the products with both the dilutedelectrolytic water and ultraviolet rays, and to a method of packagingproducts with packaging members sterilized by the above process.

With the method of sterilizing products according to the presentinvention, outstanding benefits are obtained such as that 1) since noresidue of sodium chloride is left after sterilization, there is noconcern regarding rusting of metallic surfaces of the equipment due tosodium chloride, 2) since the electrolytic water is practically neutraland of low chlorine concentration, there is little corrosion of metallicsurfaces due to oxygen and chlorine and the safety of the workingenvironment is high, and 3) there is little risk of denaturing theproducts, and the treatment time is short.

Also, the method of packaging products according to the presentinvention has outstanding benefits such as that 1) since there is noresidue of sodium chloride after packaging, there is no denaturing ofproducts due to sodium chloride, and, in addition, there is no concernregarding rusting due to sodium chloride of the metallic surfaces of thepackaging equipment, 2) since the electrolytic water that is used ispractically neutral and of low chlorine concentration, there is littlelikelihood of corrosion due to oxygen and chlorine of metallic surfacesof the packaging equipment, and safety of the working environment ishigh, and also 3) it is suited to mass treatment.

An object of the present invention is to provide a method of sterilizingproducts using in combination electrolytic water and ultraviolet rays,which little denatures the products, little concerns with rust andcorrosion of the equipment, permits a safe working environment, and canshorten the treatment time.

A further object of the present invention is to provide a method ofhygienic packaging products combining the use of electrolytic water andultraviolet rays, which little denatures the products after packaging,little concerns with rust and corrosion and the like of the packagingequipment, permits a safe working environment, and which is suited tomass treatment.

In order to solve the above problem, according to a first aspect of thepresent invention there is provided a method of sterilizing products,which comprises adding hydrochloric acid to water not containing sodiumchloride, passing the resulting fluid through a diaphragm-lesselectrolytic bath, subjecting the resulting fluid to electrolysis,collecting the electrolytic water, diluting the electrolytic water withwater, and then sterilizing the products with both the dilutedelectrolytic water and ultraviolet rays.

Also, in preferred embodiments of the first aspect of the presentinvention, the products are sterilized by bringing diluted electrolyticwater into contact with the surface of the products, and thenirradiating the products with ultraviolet rays (hereinbelow called thefirst embodiment), the diluted electrolytic water is of active chlorineconcentration 3 to 50 ppm, in particular under 20 ppm (hereinbelowcalled the second embodiment) and the diluted electrolytic water isneutral (hereinbelow called the third embodiment).

In order to solve the above problem, according to a second aspect of thepresent invention, there is provided a method of packaging products bymeans of a hygienic packaging member, which comprises addinghydrochloric acid to water not containing sodium chloride, passing theresulting fluid through a diaphragm-less electrolysis bath, subjectingthe resulting fluid to electrolysis, collecting the electrolytic water,diluting the electrolytic water with water, bringing the dilutedelectrolytic water into contact with the packaging member, irradiatingthis packaging member with ultraviolet rays, and then packing theproducts by the sterilized packaging member.

Also, according to preferred embodiments of the second aspect of thepresent invention, the diluted electrolytic water is of active chlorineconcentration 3 to 50 ppm, in particular under 20 ppm (hereinbelowcalled the fourth embodiment), the diluted electrolytic water ispractically neutral (hereinbelow called the fifth embodiment) and thepacking member is irradiated with ultraviolet rays for under 10 seconds(hereinbelow called the sixth embodiment).

Next, the present invention will be described in more detail.

A first aspect of the present invention consists in a method ofsterilizing products. According to a first aspect of the invention,first of all, hydrochloric acid is added to water that does not containsodium chloride. In this context, the term “water” means tap water,underground water, underflow water, desalted water, distilled water, ormixtures of these and the like which contain essentially no sodiumchloride. “Which contain no sodium chloride” means that no sodiumchloride has been deliberately added; traces of chlorine ions and sodiumions naturally contained in the water are not taken into account.

This aqueous solution of hydrochloric acid is passed through adiaphragm-less electrolytic bath where electrolysis is conducted andfrom which electrolytic water is collected. This electrolytic water ofcourse contains no sodium chloride. The above operation may be conductedby arranging a tank in which is stored hydrochloric acid of 21%concentration (by weight; Also hereinbelow unless otherwise speciallyindicated) in a PURE STAR (Trademark; manufactured by MorinagaEngineering Co., Ltd.), for example, which is a commercially availableelectrolytic water manufacturing device, supplying hydrochloric acid andtap water thereto, and continuously conducting electro-decomposition,the electrolytic water obtained being then diluted to adjust the activechlorine concentration to the prescribed range.

According to the present invention, products are sterilized by acombination of the electrolytic water which is thus obtained andultraviolet ray irradiation. Preferably the irradiation with ultravioletrays is conducted for no more than 10 seconds. In the prior art referredto above irradiation for more than 10 seconds was necessary, but, withthe present invention, as will be clear from the embodiment given below,even when the concentration of active chlorine in the electrolytic wateris low, a satisfactory sterilizing effect is obtained with ultravioletray irradiation of no more than 10 seconds, in particular, of a time of2 seconds or less.

With the method of the present invention, since the electrolytic watercontains no sodium chloride, there is no possibility of sodium chloridebeing left behind after sterilization of the products. There istherefore little risk of altering the quality of the products. Also,regarding equipment, this can withstand use for a long period withoutoccurrence of the various troubles caused by sodium chloride, such asrusting of metallic surfaces.

In a first preferred embodiment of the present invention, the product issterilized by bringing the surface of the product into contact withelectrolytic water, then irradiating with ultraviolet rays. “Bringinginto contact” in this case means an operation in which electrolyticwater is made to adhere to the surface of the product; examples are anoperation in which electrolytic water is sprayed or applied to thesurface of the product, or an operation in which the product is immersedin electrolytic water, etc.

Also, a step may be added in which electrolytic water adhering to theproduct is dried before or after irradiating with ultraviolet rays.

In a second preferred embodiment of the present invention, electrolyticwater of active chlorine content 3 to 50 ppm is employed.

In general, in the manufacture of electrolytic water, the pH and activechlorine concentration are determined by the following expressions (i)and (ii).

C _(P) =I·70.9·1000/2F·V  (i)

C _(R)=(2F·C·vc−I)/2F·V  (ii)

[Where, in the above expressions, C_(P) indicates the amount of chlorinegenerated (ppm), I indicates the current (ampere), F indicates theFaraday constant, V indicates the amount of electrolyzed watermanufactured, C_(R) indicates the concentration of chlorine in theelectrolytic water, C indicates the concentration of the undilutedhydrochloric acid (21%), and vc indicates the flow amount of undilutedhydrochloric acid, respectively.]

From the above expression (i), it can be seen that increasing the amountof supply of water decreases the concentration of active chlorine, andincreasing the current increases the concentration of active chlorine,and from expression (ii) it can be seen that increase of the amount ofsupply of hydrochloric acid or decrease of the current results inincrease of the density of hydrochloric acid, while increase of theamount of manufacture of electrolytic water decreases the concentrationof hydrochloric acid. Electrolytic water of the desired concentration ofactive chlorine can therefore be obtained by suitably adjusting theamount of supply of hydrochloric acid, amount of supply of water, andcurrent, or by diluting the electrolytic water after electrolysis.

In general, in water in which chlorine is dissolved, the chlorine takesthree modes, namely, molecular chlorine, hypochlorous acid, andhypochlorous acid ions; the proportion in which these are presentchanges depending on the pH value, but, of these three modes,hypochlorous acid is said to have the strongest sterilizing effect(“Hygiene Test Methods Annotated And Explained 1990” published by theJapanese Pharmaceutical Association (Nippon Yaku Gakkai), page 946, Mar.31, 1990).

The present invention makes use of the powerful sterilizing action ofhypochlorous acid, and enables this to be employed in a range of activechlorine concentration of 3 to 50 ppm. Also, a fully satisfactorysterilizing effect is obtained even in a low range of active chlorineconcentration i.e. less than 20 ppm and in particular, as will be clearfrom the following test examples, a range of 3 ppm to 20 ppm isparticularly suitable. Specifically, since, with the method ofsterilization of the present invention, the chlorine concentration ofthe electrolytic water is lower than in the prior art, there are thebenefits that there is no chemical smell after sterilization ofproducts, there are no adverse effects due to chlorine even if it comesinto contact with the hands of the workers, and there is little concernregarding corrosion due to chlorine of metallic surfaces etc. of theequipment; thus all in all, its safety in regard to products, equipmentand working environment is high.

In a third preferred aspect of the present invention, the electrolyticwater is employed in practically neutral condition. “Practicallyneutral” means a pH range of 5.0 to 6.5; in this range, theconcentration of hypochlorous acid referred to above is highest. Also,materials of poor resistance to acidity can also be employed in theequipment and the electrolytic water is safe even when it comes intocontact with the skin of workers.

A second aspect of the present invention consists in a hygienic productpackaging method utilizing the sterilization method constituting a firstaspect of the invention.

According to the second aspect of the invention, electrolytic water isprepared, not containing sodium chloride, just as in the case of thefirst aspect of the invention. The packaging member is then sterilizedby bringing this electrolytic water into contact with the packagingmember, followed by irradiating it with ultraviolet rays. After thepackaging member has been sterilized, the product is packaged byordinary methods to obtain the package.

Since the electrolytic water employed in the present invention does notcontain sodium chloride, there is no possibility of common salt beingleft behind on the packaging member, so there is absolutely no risk ofdenaturing of the product due to sodium chloride.

Also, since there is little rusting of metallic surfaces due to residualsodium chloride, the packaging equipment can be used over a long time;this is also advantageous from the point of view of maintenance andmanufacturing costs.

According to a fourth aspect of the present invention, electrolyticwater of active chlorine concentration 3 to 50 ppm, preferably 3 ppm to20 ppm is employed. According to the present invention, electrolyticwater of low active chlorine content can be employed. Consequently, thevarious troubles caused by chlorine are minimized and high safety isachieved in regard to the equipment and working environment.

According to a fifth aspect of the present invention, the electrolyticwater used is employed in a practically neutral condition. Materials ofpoor resistance to acids can therefore be employed in the packagingequipment and it is safe even if allowed to come into contact with theskin of workers.

According to a sixth aspect of the present invention, irradiation byultraviolet rays is conducted for up to 10 seconds, preferably for atime of under 2 seconds. As mentioned above, according to the presentinvention, irradiation with ultraviolet rays for a short time is fullysufficient and, as a result, in particular when processing using acontinuous process, treatment speed is increased, enabling productioncapacity to be raised.

It should be noted that there are no restrictions regarding the type ofpackaging member according to the present invention and, apart frompaper containers as mentioned above, it could be applied to variouspackaging members such as molded plastics containers, bottles, cans,paper sheet, or laminate.

Also, in the present invention, it is desirable that the diaphragm-lesselectrolytic bath should be a multi-electrode type electrolytic bath.

In general, there are two types of arrangement whereby a plurality ofelectrodes may be coupled in an electrolytic bath, namely, asingle-electrode arrangement and a multi-electrode arrangement. Thesingle-electrode arrangement is an arrangement in which all of theelectrodes are connected to one or other of the negative terminal orpositive terminal of the power source; the multi-electrode arrangementis an arrangement in which for example there is provided a constructionin which a plurality of electrodes are superimposed with fixedseparations, being mutually insulated, there being at least oneintermediate electrode, that is not connected to either terminal,between the electrodes (i.e. positive electrodes) connected to thepositive terminal of the power source and the electrodes (i.e. negativeelectrodes) connected to the negative terminal of the power source.

Also, in this case, it is desirable that, when conducting electrolysis,the voltage per electrode pair should be at least 1.5 volts and lessthan 4.0 volts. In the case of a multi-electrode electrolytic bath, asmentioned, an intermediate electrode is present between the negativeelectrode and positive electrode, but the term “voltage per electrodepair” means the voltage between two adjacent electrodes, including thenegative electrode, positive electrode and intermediate electrode.

In general, when the voltage of the electrolytic bath is raised,chlorine starts to be generated at 1.3 volts or more, and the maximumrate of evolution is reached at 1.5 volts or more. It is thereforedesirable that the voltage per electrode pair should be at least 1.5volts. Also, if the voltage exceeds 4.0 volts, oxygen starts to begenerated and if 5.0 volts is exceeded, ozone starts to be generated.Generation of ozone is undesirable and generation of oxygen wastespower, so preferably the voltage should be below 4.0 volts. From theeconomic viewpoint, in particular, it is preferable that the voltageshould be below 3.0 volts.

Next, the present invention will be described in detail with referenceto test examples.

TEST EXAMPLES

These tests were conducted in order to ascertain the relationshipbetween the sterilization conditions of the packaging member in a methodof packaging of products according to the present invention and thesterilization effect.

1) Preparation of Samples

Samples of cream soup in paper containers were manufactured by the samemethod as in the case of Example 1, to be described, using the papercontainer filling machine 1 illustrated in Example 1 (see FIG. 1), withthe exception that, by altering the current of the diaphragm-lesselectrolytic bath 14 in electrolytic water generating system 10 andaltering the degree of dilution of the electrolytic water, the activechlorine concentration of the electrolytic water was altered to 2.0 to20.0 ppm as shown in Table 1 and, by altering the feed speed of conveyorbelt 2, the ultraviolet ray irradiation time was altered to 0.5 to 25.0seconds as shown in Table 1. These were taken as samples of the presentinvention.

Also, as a comparative example, samples of cream soup packed in papercontainers were manufactured by the same method as in Example 1 below byadding common salt to a diaphragm-less electrolytic bath 14 and usingthe electrolytic water obtained by electrolysis (active chlorineconcentration 25.0 ppm) in the same way, irradiating with ultravioletrays for 0.5 to 25.0 seconds. These were taken as comparative examplesamples.

2) Test Methods

(1) Flavor Test

The flavor of the samples according to the present invention and thecomparative samples were compared by a flavor panel of 20 men and women.

(2) Storage Test

The samples obtained were all stored in a refrigerator at 10° C., thepackages opened on the 14th day, and the flavor ascertained, and thenumber of ordinary bacteria and the number of psychrophillic bacteriadetermined by the ordinary methods (“Food Product MicroorganismHandbook”, pages 560 to 576, published by Gihodo Shuppan CompanyLimited, Nov. 1, 1995, compiled by Yoshii et al.), the satisfactorinessof the product being thereby determined.

3) Test Results

(1) Flavor Test

Six of the 20 flavor panelists evaluated the sample of the comparativeexample as having a bad flavor apparently due to salt, chlorine oracidity.

As a supplementary opinion, of the samples according to the presentinvention, three panelists evaluated the samples whose active chlorineconcentration was under 19.5 ppm as having better flavor than thosewhose active chlorine concentration was 20.0 ppm.

(2) Storage Test

The results of this test are shown in Table 1. Table 1 is a Tableshowing the relationship between the sterilization conditions (activechlorine concentration of the electrolytic water and ultraviolet rayirradiation time) of a packaging member in the method of packagingproducts according to the present invention and storage characteristicsafter packaging. In Table 1, ◯ indicates samples that were found to begood products, being negative in respect of ordinary bacteria andpsychrophillic bacteria and × indicates samples that were found to bedefective products on account of one or other or both of ordinarybacteria or psychrophillic bacteria being detected.

From Table 1, it can be seen that, with the samples of the presentinvention, if the active chlorine concentration of the electrolyticwater was at least 3 ppm, even if the ultraviolet ray irradiation timewas less than 10 seconds, fully satisfactory sterilization was achieved;in particular it was found that ultraviolet ray irradiation for 1.0seconds or more was ideal. It should be noted that in Table 1, of thesamples of the present invention, the range of active chlorineconcentration 3.5 to 19.0 ppm is not shown in the Table since there isno marked difference from the cases of 3 ppm and 19.5 ppm.

Regarding the sample of the comparative example, a reasonablysatisfactory sterilizing effect was found since the active chlorineconcentration of the electrolytic water was the high concentration of 25ppm.

From the above results, it was found that, with the method of packagingproducts of the present invention, there was no denaturing of the flavorof the products due to the packaging and furthermore products wereobtained whose flavor was better than that of the prior art. Also, withthe method of packaging products of the present invention, it was foundthat the active chlorine concentration of the electrolytic water waspreferably 3 ppm to 20 ppm and an ultraviolet ray irradiation time ofless than 10 seconds was fully satisfactory, 1.0 seconds or more beingparticularly preferable.

It should be noted that when similar tests were conducted in which thesterilization conditions of the cream soup and the capacity of the papercontainers etc. were altered or other food products were employed,practically identical results were obtained.

Also, in regard to sterilization of “daikon” (giant radish) described inExample 2 below, tests were conducted likewise varying in various waysthe active chlorine concentration of the electrolytic water and theultraviolet ray irradiation time, but practically identical results wereobtained; thus the test results confirmed that sterilization wasequivalent in regard to ordinary products also.

TABLE 1 Ultraviolet ray irradiation time Active chlorine (seconds)concentration (ppm) 0.5 1.0 1.5 2.0 10.0 20.0 25.0 Test 2.0 X X X X X XX examples 2.5 X X X X 0 0 0 3.0 X 0 0 0 0 0 0 19.5 0 0 0 0 0 0 0 20.0 00 0 0 0 0 0 25.0 0 0 0 0 0 0 0 Comparative 25.0 0 0 0 0 0 0 0 example

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a device for putting intopractice the method of packaging products according to the presentinvention.

EXPLANATION OF THE REFERENCE SYMBOLS

1 Paper container filling machine for cream soup

2 Conveyor

3 Paper container supply device

4 Spray system

5 Ultraviolet ray lamp

6 Remover

7 Filling nozzle

10 Electrolytic water generating system

11 Tap water supply source

12 Hydrochloric acid container

13 Hydrochloric acid pump

14 Diaphragm-less electrolytic bath

15 Gas separator

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Next, the present invention is described in detail with reference toembodiments, but the present invention is not restricted to thefollowing embodiments.

EXAMPLE 1

FIG. 1 is a diagram illustrating an example of a device (paper containerfilling machine for cream soup) for putting into practice the method ofpackaging products according to the present invention.

In FIG. 1, the paper container filling machine for cream soup isequipped with a conveyor 2 which feeds paper containers C in order inthe direction of arrow X. On the conveyor 2, in order, from the upstreamside (right-hand side in the drawing) of the conveying direction ofconveyor 2 towards the downstream side (left-hand side in the drawing)there are provided: paper container supply device 3 (carton mandrel),spray system 4, ultraviolet ray lamp 5, remover 6 and filling nozzle 7.Further downstream from filling nozzle 7, there is provided a sealingdevice that seals paper containers C, but this is not shown in FIG. 1.

Paper container supply device 3 is a device that supplies papercontainers C in formed condition. Also, the spray system 4 comprisesspray nozzles 4 a and 4 b and tank 4 c. Spray nozzle 4 a and 4 b arespray nozzles for spraying sterilizing agent into the interior of papercontainers C and are both two-fluid nozzles. However, in FIG. 1, thepiping related to the air and the flow rate adjustment valves and thelike are not shown. Tank 4 c stores sterilizing agent. Remover 6 isequipped with hot air nozzles 6 a and 6 b. Hot air is blown out of thesehot air nozzles 6 a and 6 b to dry the interior of paper container C.Filling nozzle 7 supplies sterilized cream soup to fill the papercontainers C therewith.

Paper containing filling machine for cream soup provided with the basicconstruction as above is equipped with an electrolytic water generatingsystem 19 which is characterized of the present invention.

As the electrolytic water generating system 10, the “PURE STAR”(Trademark; Manufactured by Morinaga Engineering Co., Ltd.) system wasemployed. This “PURE STAR” system is equipped with tap water supplysource 11, hydrochloric acid container 12, hydrochloric acid pump 13,diaphragm-less electrolytic bath 14 and gas separator 15.

Tap water is supplied from tap water supply source 11 and mixed byhydrochloric acid pump 13 with 21% concentrated hydrochloric acid storedin hydrochloric acid container 12, and then the resulting fluid ispassed through diaphragm-less electrolytic bath 14. The electrolyticwater electrolyzed in diaphragm-less electrolytic bath 14 is mixed withtap water from dilution water line 11 a to dilute it, unwanted hydrogentherein is removed by gas separator 15, and then the resulting fluid isstored in tank 4 c.

Next, an embodiment of a method of packaging products according to thepresent invention employing the paper container filling machine forcream soup of FIG. 1 will be described.

Electrolytic water manufactured beforehand by means of electrolyticwater generating system 10, after adjusting active chlorineconcentration thereof to 14 ppm, was stored in tank 4 c. Next, papercontainers C (1-liter paper packs) are supplied from paper containersupply device 3 (carton mandrel) and fed in the direction of the arrow Xsequentially by means of conveyor 2.

Electrolytic water stored in tank 4 c is sprayed on to the inner surfaceof paper containers C under the condition of flow rate 300 ml/h fromspray nozzles 4 a and 4 b, the paper containers C are passed beneathultraviolet ray lamp 5 to irradiate them for 1.5 seconds with UV-Cultraviolet rays at 50 mW.s/cm².

Next, in remover 6, the interior of paper containers C is dried byblowing out hot air of 300° C. from hot air nozzles 6 a and 6 b, andthen they are filled with cream soup sterilized with a scraping-typesterilizer under the conditions: 130° C., 2 seconds, from filling nozzle7. They are then sealed by a sealing device (not shown) on thedownstream side. Cream soup product packed in the paper container of 1liter capacity was thereby manufactured with a production capacity of6000 pieces per hour.

EXAMPLE 2

Electrolytic water, whose active chlorine concentration was adjusted to13 ppm, was manufactured with a system 10 for generating electrolyticwater not containing sodium in FIG. 1 referred to above, and stored in avat.

Commercially available whole daikon (radish; length about 40 cm) wasintroduced into the vat and immersed in the electrolytic water for 10minutes, and then the radish was pulled up out of the electrolyticwater, placed in the front of three ultraviolet ray lamps 5 to irradiateit with ultraviolet rays for 5 seconds, and then immediately dried bydirecting a current of air at normal temperature with a drier.

Before and after performing the above operation on ten radishes forsubjecting each radish to sterilizing treatment, the 5 cm square of thesurface of each radish was wiped with sterilized gauze of 5 cm×5 cm, andthe gauze was introduced into 10 ml of sterilized physiological salinesolution containing sodium thiosulfate in 0.5% concentration; thissolution was diluted by the ordinary method and cultured for 48 hours at35° C. using a standard agar medium, and then the number of livebacteria thereof was determined by the ordinary method.

The results obtained above were converted into results for a 10 cmsquare wiping area and the number of live bacteria before and aftersterilization of each radish were compared. As a result, it was foundthat, whereas the number thereof before sterilization was a mean of1,000,000 cfu/100 cm², the number thereof after sterilization was a meanof 1,000 cfu/100 cm², representing a reduction of about {fraction(1/1,000)}. Thus it was confirmed that in every case fully satisfactorysterilization thereof was achieved.

Comparative Example

10 radishes were sterilized in the same way as in the Example 2, exceptsterilizing the radishes with only electrolytic water and withoutperforming irradiation with ultraviolet rays, and then the number oflive bacteria thereof before and after sterilization were compared inthe same way. As a result, it was found that, whereas the mean beforesterilization was 1,000,000 cfu/100 cm², the mean after sterilizationwas 10,000 cfu/100 cm², representing a reduction of only {fraction(1/100)}. Similar results were obtained even if the immersion time inthe electrolytic water was lengthened or the sterilizing operation wasrepeated.

INDUSTRIAL APPLICABILITY

The benefits presented by the present invention are as follows.

(1) With the method of sterilizing products according to the presentinvention, no sodium chloride is left after sterilization, so there isno concern regarding rusting of metallic surfaces of the equipment dueto sodium chloride. This is therefore advantageous in that the equipmentcan withstand prolonged use and in terms of maintenance andmanufacturing costs.

(2) With the method of sterilizing products according to the presentinvention, the electrolytic water is practically neutral, and thechlorine concentration is low, so there is little corrosion of metalsurfaces due to oxygen or chlorine and the safety of the workingenvironment is high.

(3) With the method of sterilizing products according to the presentinvention, the risk of denaturing the products is small and treatmenttime is short.

(4) With the method of packaging products according to the presentinvention, there is no residue of sodium chloride after packaging and nodenaturing of the products due to sodium chloride and furthermore thereis no concern regarding rusting of the metallic surfaces of thepackaging equipment due to sodium chloride. Consequently, the packagingequipment can withstand prolonged use and advantages are obtained inrespect of maintenance and manufacturing costs.

(5) With the method of packaging products according to the presentinvention, the electrolytic water that is employed is practicallyneutral and its chlorine concentration is low, so there is littlelikelihood of corrosion of the metallic surfaces of the packagingequipment due to oxygen or chlorine and the safety of the workingenvironment is high.

(6) The method of packaging products according to the present inventionis suited to mass treatment.

What is claimed is:
 1. A method of packaging food or drugs by massproduction by means of a hygienic packaging member, which comprisesadding hydrochloric acid to water not containing sodium chloride,passing the resulting fluid through a diaphragm-less electrolysis bathto subject the resulting fluid to electrolysis on condition that voltageper electrode pair is below 4.0 volts, collecting the electrolytic waternot generating ozone, diluting the electrolytic water with water,sterilizing a packaging member with the diluted electrolytic water, andirradiating this packaging member with ultraviolet rays, and thenpacking the products by a sterilized packaging member.
 2. The method ofpackaging food or drugs according to claim 1, wherein the dilutedelectrolytic water not generating ozone has an active chlorineconcentration of 3 to 50 ppm.
 3. The method of packaging food or drugsaccording to claim 2, wherein the diluted electrolytic water notgenerating ozone has said active chlorine concentration of less than 20ppm.
 4. The method of packaging food or drugs according to claim 1,wherein the diluted electrolytic water not generating ozone ispractically neutral.
 5. The method of packaging food or drugs accordingto claim 1, wherein the packaging member is irradiated with saidultraviolet rays for under 10 seconds.